Preparation method of spherical calcium carbonate

Abstract

The invention discloses a preparation method of spherical calcium carbonate. The invention uses waste silk as a raw material to extract silk fibroin, then enzymatically decomposes the silk fibroin into a silk fibroin hydrolyzate, and prepares a freeze-dried powder by rotary steaming and freeze-drying. The powder is a crystal form control agent. Add the freeze-dried powder into the calcium hydroxide solution, stir and react at a constant temperature of 25-35°C for 1 hour, and then pass the mixed gas of CO2 and N2 into the calcium hydroxide solution evenly to react to the pH of the solution. Reduce to 7.5-7.0, then stir at a speed lower than 200rpm for 30min, then separate the solid product and wash it with deionized water and absolute ethanol. After washing, dry it in a vacuum oven not higher than 60°C for 3h, and finally prepare Spherical calcium carbonate is obtained. The invention has the characteristics of low cost, mild preparation conditions, simple production equipment, strong operability and easy industrial production. The spherical calcium carbonate prepared by the invention has uniform particle size and good dispersibility.

Description

technical field [0001] The invention belongs to the field of inorganic non-metallic materials, and in particular relates to a preparation method of spherical calcium carbonate. Background technique [0002] Calcium carbonate is one of the inorganic minerals ubiquitous in nature. As an important inorganic material, calcium carbonate has the advantages of low cost, non-toxic and harmless, high whiteness, controllable shape, stable chemical properties, etc. It can be used as a coating pigment, extender, and filler, and is widely used in Plastics, building materials, paper, rubber, ink, adhesives, food, daily chemicals, medicine and other fields. [0003] In recent years, in terms of chemistry and materials, synthetic inorganic microspheres have attracted more and more attention because of their low density, small volume, large specific surface area and void volume, mechanical and thermal stability, and certain surface penetration. has become a hot research topic at present. ...

AI Technical Summary

Problems solved by technology

Chinese patent (CN102557100A) has announced a kind of production method of spherical calcium carbonate, is to be crystal formation control agent with pentaerythritol, sodium carbonate solution is slowly added in the calcium chloride solution, reacts and generates nano-spherical calcium carbonate, and this reaction production cost is high , the reaction process is fast, uncontrollable, and the by-product pollution is serious, so it is rarely used in industrial production at present

[0005] Luo J, Kong F, Ma X's literature Role ofAspartic Acid in the Synthesis ofSpherical Vaterite by the Ca(OH) 2 –CO 2 Reaction[J].Crystal Growth&Design, 2016,16(2) discloses a method for preparing calcium carbonate with aspartic acid as crystal form control agent by carbonization method, aspartic acid is chelated with calcium ion by carboxyl group, Provide nucleation sites, regulate the generation of spherical calcium carbonate, and prepare spherical calcium carbonate with small particle size. The calcium carbonate formed by the reaction of free calcium ions in the solution directly with carbonate is calcite type, mostly cubic, and the preparation process In China, pure amino acid is used as the crystal form control agent, which is expensive and has high production cost, so it is not suitable for industrial production

The literature Biomineralization of stable and monodisperse vateritemicrospheres using silk nanoparticles[J] by LiuL, Zhang X, Liu X, etc. discloses a metathesis method in Acs Applied Materials&Interfaces, 2015, 7(3): 1735, using silk fibroin as the crystal form control agent to generate stable and monodisperse spherical calcium carbonate. During the reaction, silk fibroin chelates calcium ions through carboxyl groups to provide nucleation sites and react with carbonate ions to regulate the production of spherical calcium carbonate. Silk fibroin is a macromolecule. Compared with polypeptides and amino acids of the same quality, the content of carboxyl groups is less. To chelate the same calcium ion, more silk fibroin is needed and the cost is higher.

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